The Seismic Response Of Span Continuous Rigid Frame Bridge In The Long-period Earthquake

Along with the development of our country bridges, a rapid increase in the number of domestic large-scale bridges, bridge systems are quietly undergoing changes:a greater span, pier higher, the overall stiffness of smaller, more beautiful shape. Accordingly leads to a new topic:structural natural periods greater, more intense seismic response, seismic measures more complex. In addition our country large and strong seismic activity, accounting for almost one-third of the world's total continental earthquakes. Recent Wenchuan earthquake in China, seismic waves were comparatively rich long-period components that have been built long-span bridges caused major damage, and also exposed many problems, long-span bridges in the long-period earthquakes in the seismic problem is increasingly difficult. In view of this, this paper span continuous rigid frame bridge as the research object for the following areas of study:(1)establish for the content of the six space of finite element model,and do analysis various vibration characteristics of model structure;(2) for long-period seismic wave characteristics, do input the model contains more long-period components of seismic wave dynamic analysis, and input common period seismic waves in the dynamic analysis were compared;(3)do the structure of the pile-soil-structure interaction effect analysis and traveling wave effect analysis;(4) change the pier height parameters, for different input of the model contains more long-period components of seismic wave dynamic analysis, and with the corresponding period of input seismic waves of ordinary dynamic analysis were compared.Through the above analysis, some conclusions are drawn, as follows:(1)span continuous rigid frame bridge components in more long-period seismic waves, transverse to the internal force and displacement response of greatly increased;(2) considering pile-soil-structure interaction, the structure of the fundamental frequency decreases, extend the natural cycle, displacement of the structures increases,and also the main beams internal forces; (3)considering wave effects, internal force and displacement have large changes,in particular large increases in local peak;(4) adjusting span continuous rigid frame bridge pier height parameters, with the height of piers and the reduction of structural natural periods decrease, long-period seismic waves on the structure of the local response to the increasing effect of decreases.Hope that through the above analysis of the structure of the same type of seismic design and research will provide some help and reference.